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4 years ago

52. How did people spend Life in thehunting age-

Physics

2 answers:

kondor19780726 [428]4 years ago

7 0

Answer:

what is the hunting age? i've never heard of it

Rufina [12.5K]4 years ago

7 0

Mostly as a nomadic people, traveling from place to place and following the herds that they hunt from.

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How are motors and generators different?

saw5 [17]

A generator converts mechanical energy into electrical energy, while a motor does the opposite - it converts electrical energy into mechanical energy

4 0

3 years ago

A modern compact fluorescent lamp contains 1.4 mg of mercury (Hg). If each mercury atom in the lamp were to emit a single photon

Reika [66]

Answer:

A. 1.64 J

Explanation:

First of all, we need to find how many moles correspond to 1.4 mg of mercury. We have:

$n=\frac{m}{M_m}$

where

n is the number of moles

m = 1.4 mg = 0.0014 g is the mass of mercury

Mm = 200.6 g/mol is the molar mass of mercury

Substituting, we find

$n=\frac{0.0014 g}{200.6 g/mol}=7.0\cdot 10^{-6} mol$

Now we have to find the number of atoms contained in this sample of mercury, which is given by:

$N=n N_A$

where

n is the number of moles

$N_A=6.022\cdot 10^{23} mol^{-1}$ is the Avogadro number

Substituting,

$N=(7.0\cdot 10^{-6} mol)(6.022\cdot 10^{23} mol^{-1})=4.22\cdot 10^{18}$ atoms

The energy emitted by each atom (the energy of one photon) is

$E_1 = \frac{hc}{\lambda}$

where

h is the Planck constant

c is the speed of light

$\lambda=508 nm=5.08\cdot 10^{-7}nm$ is the wavelength

Substituting,

$E_1 = \frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{5.08\cdot 10^{-7} m}=3.92\cdot 10^{-19} J$

And so, the total energy emitted by the sample is

$E=nE_1 = (4.22\cdot 10^{18} )(3.92\cdot 10^{-19}J)=1.64 J$

4 0

3 years ago

if vector u has lenght 70 and direction 40 degrees, and vector v has length 85 and direction 335 degrees what is the length and

Anastaziya [24]

Answer:

Magnitude of resultant = 131.15

Direction of resultant = 3.97°

Explanation:

||u|| = 70

θ = 40°

$\vec{u}_x=||u||cos\theta \\\Rightarrow \vec{u}_x=70cos40=53.62$

$\vec{u}_y=||u||sin\theta \\\Rightarrow \vec{u}_y=70sin40=44.99$

||v|| = 85

θ = 335°

$\vec{v}_x=||v||cos\theta \\\Rightarrow \vec{v}_x=85cos335=77.03$

$\vec{v}_y=||v||sin\theta \\\Rightarrow \vec{v}_y=85sin335=-35.92$

Resultant

$R=\sqrt{R_x^2+R_y^2}\\\Rightarrow R=\sqrt{(\vec{u}_x+\vec{v}_x)^2+(\vec{u}_y+\vec{v}_y)^2}\\\Rightarrow R =\sqrt{(70cos40+85cos335)^2+(70sin40+85sin335)^2}\\\Rightarrow R =131.15$

$\theta=tan^{-1}\frac{R_y}{R_x}\\\Rightarrow \theta=tan^{-1}\frac{70sin40+85sin335}{70cos40+85cos335}\\\Rightarrow \theta=tan^{-1}0.069=3.97^{\circ}$

Magnitude of resultant = 131.15

Direction of resultant = 3.97°

4 0

3 years ago

To drive your car from Auburn to Atlanta (173.8 km) takes a significant amount of work. Assuming the force of friction between t

Daniel [21]

Answer:

1788.402 MJ

Explanation:

Work done = Force (N) x distance (m)

First we have to convert distance into metres:

173.8 x 1000 = 173,800 m

Then plug these values into the equation above:

173,800 x 10290 = 1788402000 J

The reason it's Joules (the unit for energy) is because work done = energy transferred

Now we have to convert Joules into Mega Joules:

1 J = 1/1000000 MJ

1788402000 J = 1788402000/ 1000000 = 1788.402 MJ

5 0

3 years ago

The angle between incident ray and reflected ray is 130.what is the value of angle of incidence

Artyom0805 [142]

Answer:

Explanation:

as i = r , so i + i = 130

so , i = 130/2 =65

7 0

3 years ago

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52. How did people spend Life in thehunting age-​

52. How did people spend Life in thehunting age-